U.S. Pat. No. 5,354,169 issued Oct. 11, 1994, to Washio, et al., discloses a gantry crane which is rollably mounted upon parallel tracks for longitudinal transport. In Washio, sessile cantilevered storage racks are erected between the gantry carrying tracks, such racks being utilizable for storage of long stock materials such as timbers and pipes. In operation of the assembly disclosed in Washio, et al., its gantry crane straddles and overrides the cantilevered storage racks. A crossbeam which horizontally supports and extends cantilevered material handling arms, similar to those of a common forklift, is suspended by cables from the upper structural cross member of the gantry; the cables providing alternate upward and downward motion of the crossbeam through the action of a winch. Through rolling motion of the gantry crane in Washio, and through operation of its fork bearing crossbeam, materials stored in the cantilevered storage racks may be alternately stored and removed. The storage system disclosed in Washio results in undesirable waste of useful storage space, requiring a series of permanent aisles between the cantilevered storage racks for operation of the gantry crane. The instant inventive storage assembly solves such space utilization problem by combining a rollable gantry lift with mechanisms and means for packable and separateable storage racks, eliminating the space wasting series of aisles.